• International Journal of Highway Engineering
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• v.16 no.1
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• pp.41-48
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• 2014

PURPOSES : The lane width of the domestic highway is 3.5 ~ 3.6m and it has been designed nationwide. However, the distribution of the average vehicle widths, rearview mirror widths and lateral wheel paths by region appear different. Then, lane spare widths may differ by region followingly. Thus, the flexible design of freeway lane widths is required. METHODS : The methodologies of this paper are as follows. First, vehicle widths rearview mirror widths lateral wheel paths of vehicles driven four national expressways were measured. Second, lane spare widths by vehicle widths were calculated. Third, lane spare widths reflecting rearview mirror widths were calculated by using interval estimation. Additionally, lane spare widths reflecting vehicles lateral wheel paths were calculated. RESULTS : The results of this paper are as follows. First, lane spare widths by vehicle widths ranges 0.83 to 0.95m. Second, lane spare widths reflecting rearview mirror widths ranges 0.518 to 0.747m at the confidence interval 95%. Third, lane spare widths reflecting vehicles' lateral wheel paths ranges -0.022 to 0.322m at the curved sections and the confidence interval 95%. CONCLUSIONS : It may be concluded that the present lane spare widths are relatively narrow at the curved section. Thus, there is a need to consider expanded lane widths at the curved sections. Additionally, there is a need to consider flexible design of lane widths by various conditions.

• International journal of advanced smart convergence
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• v.11 no.2
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• pp.219-225
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• 2022

Recently, the popularization of personal mobility(PM) has made it possible to see many electric scooters. The energy source of personal transportation used by the general public and the disabled can be seen as environmentally friendly as electricity. Personal transportation means are divided into small electric vehicles because they use electric energy, and they are being treated as new models by automobile manufacturers in each country and spurring development. On the other hand, personal transportation means may cause various types of traffic accidents as they travel between roads and a human walk. In order to prevent such accidents, it is judged that the enactment of laws on the establishment of specifications for electric scooters, which are personal transportation means, and the method of restricting road operation should be given priority. The electric scooter is basically different from the conventional vehicle. The steering shaft of the steering system applied to the electric scooter one to two is possible. 1 to 2 the front-wheel under the steering column is used. It is classified according to the number of wheel installed at the electric scooter is the vehicle body into 2 wheel - electric scooter, and 3 wheel - electric scooter and 4 wheel - electric scooter. In this study, we propose a steering shaft design model that can be applied to an electric scooter, one of personal transportation means. A design model for 1-shaft steering and 2-shafts steering that can be applied to electric scooters is proposed. In addition, we have produced the prototypes for the commercialization of the proposed models, and reviewed the pros and cons of the manufactured prototypes and models.

• International Journal of Automotive Technology
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• v.5 no.2
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• pp.123-133
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• 2004

This paper describes a robust and fast wheel slip tracking control using a moving sliding surface technique. A traction control system (TCS) is the active safety system used to prevent the wheel slipping and thus improve acceleration performance, stability and steerability on slippery roads through the engine torque and/or brake torque control. This paper presents a wheel slip control for TCS through the engine torque control. The proposed controller can track a reference input wheel slip in a predetermined time. The design strategy investigated is based on a moving sliding surface that only contains the error between the reference input wheel slip and the actual wheel slip. The used moving sliding mode was originally designed to ensure that the states remain on a sliding surface, thereby achieving robustness and eliminating chattering. The improved robustness in driving is important due to changes, such as from dry road to wet road or vice versa which always happen in working conditions. Simulations are performed to demonstrate the effectiveness of the proposed moving sliding mode controller.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.789-797
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• 2004

The wear and defects on the wheel tread are caused by the interface between wheel and rail, the suspension system on bogie, the track condition and etc, which are interacted with complex mechanism. Because of the difficulty of analysis of wheel and rail interaction, the measuring data are necessary for improvement of wheel design and maintenance of train. On this case study, the pattern of wheel wears and defects are presented and lifetime of wheel and the reprofiling period are estimated on a basis of the measured results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.6
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• pp.750-755
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• 2013

In-wheel motor system gets the driving force from direct-driven motor in the wheel of electric vehicle. It is known as good system for vehicles, from an efficiency, packaging, handling and safety. This paper describes motor and inverter technologies, system configuration and control algorithms for in-wheel type electric vehicle. It is necessary to control on an interrelation perspective because this system drives two motors at same time. In system design, IPMSM(Interior Permanent Magnet Synchronous Motor) including a wide operating range and high-speed rpm is used and flux weakening control is performed in constant power range. Under the torque command from the host controller, auto control box, inverter's output torque is calculated with using torque estimation technique and applied to actual vehicle driving system. It is verified that the configuration and the algorithm are suitable for the in-wheel motor system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.310-316
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• 2016

We propose a novel contact-free transportation system in which an axial electrodynamic wheel is applied as an actuator. When the electrodynamic wheel is partially overlapped by a fixed conductive plate and rotates over it, three-axis magnetic forces are generated on the wheel. Among these forces, those in the gravitational direction and the lateral direction are inherently stable. Therefore, only the force in the longitudinal direction needs to be controlled to guarantee spatial stability of the wheel. The electrodynamic wheel consists of permanent magnets that are repeated and polarized periodically along the circumferential direction. The basic geometric configuration and the pole number of the wheel influence the stability margin of a transportation system, which would include several wheels. The overlap region between the wheel and the conductive plate is a dominant factor affecting the stiffness in the lateral direction. Therefore, sensitivity analysis for the major parameters of the wheel mechanism was performed using a finite element tool. The system was manufactured based on the obtained design values, and the passive stability of a moving object with the wheels was verified experimentally.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.6
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• pp.95-103
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• 2006

Wheel treads of E.M.U. are usually under a heavy thermal load by brake frictional heat between wheel and brake shoe and damaged by repeated thermal and mechanical loads. To examine the cause of wheel tread damage of E.M.U.'s in service running, a systematic approach has been used. This study is composed of three parts. Frictional heat analysis was conducted in the first part by finite element method. Two kinds of brake shoes in service were considered. In the second part, experimental study was carried out on a brake dynamometer. Temperatures were measured for the two brake shoes. And experimental study in service running E.M.U.'s was performed. Wheel and brake shoe temperatures were measured by using thermocouples and temperature indicating strips. Finally metallurgical characteristics were examined by a SEM/EDS and the cause of the wheel damage was analyzed. It seems that aggregated ferrous component is a main cause of the wheel tread damage.

• Aerospace Engineering and Technology
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• v.9 no.2
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• pp.51-56
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• 2010

There are two main software in COMS ground station at the normal mode operation - stationkeeping and wheel off-loading. In this paper, ground software validation test for wheel off-loading is summarized and described. The wheel off-loading was performed the design change from E3000 heritage and analyzed. The wheel off-loading of ground software has two part; one is wheel off-loading management for parameters change at the thruster set switching time and the other is wheel off-loading set-point being sent to satellite for the reference momentum.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.12
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• pp.1225-1231
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• 2009

One reaction wheel cluster of satellite usually has four reaction wheels. Each wheel is not arranged parallel to the attitude axis of satellite. Therefore, if one reaction wheel is broken, it is very hard to isolate the fault except using the sensors of wheel itself. In this paper, the isolator of satellite reaction wheel cluster is designed. Using a dual filter, FDP(Fault Detection Parameter) is made to detect fault, and using a multi-hypothesis extended Kalman filter, fault isolation of wheel cluster is done. We verify the improvement of isolation performance of wheel cluster by simulation with 4-reaction wheel cluster.

• The Journal of Korea Robotics Society
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• v.15 no.3
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• pp.221-232
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• 2020

In a four-wheel independent drive platform, four wheels and motors are connected directly, and the rotation of the motors generates the power of the platform. It uses a skid steering system that steers based on the difference in rotational power between wheel motors. The platform can control the speed of each wheel individually and has excellent mobility on dirt roads. However, the difficulty of the straight-running is caused due to torque distribution variation in each wheel's motor, and the direction of rotation of the wheel, and moving direction of the platform, and the difference of the platform's target direction. This paper describes an algorithm to detect the slip generated on each wheel when a four-wheel independent drive platform is traveling in a harsh environment. When the slip is detected, a compensation control algorithm is activated to compensate the torque of the motor mounted on the platform to improve the trajectory tracking performance of the platform. The four-wheel independent drive platform developed for this study verified the algorithm. The wheel slip detection and the compensation control algorithm of the platform are expected to improve the stability of trajectory tracking.